Blood Shadow, a top assassin, is betrayed by her organization and detonates an explosion on an isolated island before being reborn as Qiao Ying, a bullied girl. Facing poverty, cruel relatives, and humiliation at school, she loses weight and transforms herself, fighting back fiercely with her medical skills, hacking, mathematics, and combat abilities. She protects her younger brother and joins forces with Qin Hanyue, a powerful figure, to investigate the truth behind the shadows. Amid clashes and growing attraction, she rises to the top once more. She exposes conspiracies, settles accounts with her enemies, and gains both family affection and love.